Dice soy or nondairy butter finely; place in freezer to chill.
Mix coconut milk and apple cider vinegar; set aside to let curdle and thicken.
Preheat oven to 400 degrees.
In a large bowl, mix flour, baking powder, sugar and sea salt.
With your fingers or fork or pastry blender, work in chilled nondairy butter until it resembles coarse meal. Stir in coconut milk mixture, orange zest and orange juice, egg yolk, and poppy seeds, stirring just until combined.
On a lightly floured surface, knead dough several times, shape into a large circle and cut wedges.
Place scone triangles onto cookie sheets and if desired, brush with egg and sprinkle with sugar. Bake at 400 degrees 12-16 minutes or until light golden in color.